In many shallow aquifers, groundwater has been contaminated by anthropogenic (man-made) sources and/or natural processes (e.g., weathering, sorption/desorption, and biogeochemical reactions) to the point where the water from the aquifer is unsuitable for safe and healthy human consumption. Water from contaminated aquifers may even be unsuitable for agricultural uses such as watering livestock or irrigation, or for many industrial purposes. In many countries, a significant portion of the population (estimated to be greater than 100 million people world-wide) have no viable alternative to using this contaminated water for human consumption and for livestock, leading to potentially adverse living conditions and negative health effects.
The demand for clean water is only expected to increase in coming years due to global population increases. Thus, new technologies are required to help remove contaminants from available groundwater supplies. In developed countries, concerns about water quality have led to increased usage of bottled water from uncontaminated or filtered/purified sources for drinking purposes. Technologies have also been developed to remove even trace amounts of dissolved contaminants from water (e.g., water filters, etc.). However, in developing countries the cost of known active water-treatment technologies for groundwater is often prohibitive, often leading to significant adverse public health consequences from the consumption of untreated water.
Particular types of groundwater contaminants that have been found to be of common concern in many areas include toxic heavy metals, such as lead, cadmium, silver, hexavalent chromium, uranium, mercury etc.; toxic metalloids, such as arsenic and selenium; and halogenated hydrocarbons, such as perchloroethene (PCE) and trichloroethene (TCE). Cost-effective remediation technologies to remove these and other contaminants from groundwater drawn from aquifers through wells, to the point that the waters become clean enough for an intended use (e.g., drinking, industrial, agricultural use, etc.), would be highly desirable.
Thus, it can be seen that needs exist for improved methods and systems for processing groundwater to remove contaminants. It is to the provision of improved methods and systems meeting these and other needs that the present invention is primarily directed.